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The method to culture nail matrix cells isolated from the digits of the rats was established.1 The nail matrix cells were obtained from the digits of Fisher 344 rats aged 6 weeks and cultured by the method of dispersed cell culture, at 37ﾟC in an atmosphere of 5% CO_2/95% air. The culture dishes, which diameter was 10 cm, were not coated by anything. The Green's medium supplemented with 33% 3T3 cell's conditioned medium was used. And by this medium, the doubling time of the cultured cells was gradually shortened and the cells were cultured for a long time with few fibroblasts. The cells were plated into the culture dishes at a density of 1274 cells/cm^2. After 3 days, there were colonies composed of a few cells. After that, the cells gradually proliferated and reached confluence on day 7. Each cell looked like pavements and the colonies partially became thickened.2 The characterization of cultured nail matrix cells was examined by immunohistological reactions for the antibodies to inner or outer root sheath of hair follicle. The cultured cells showed positive reaction for the antibodies. But the reaction was gradually decreased after being cultured for a long time.3 At the same time, keratinocytes were cultured, using the same medium (the Green's medium supplemented with 33% 3T3 cell's conditioned mediume). But it was difficult to culture keratinocytes for a long time.